1. Field of the Invention
The present invention relates to a substrate processing apparatus that removes by a removal liquid an organic matter attached to a semiconductor substrate, a grass substrate for liquid crystal display, a grass substrate for photomask, and a substrate for optical disk (hereinafter referred to simply as a “substrate”). Included in such organic matter is polymer that is formed by subjecting a thin film existing on the substrate surface to dry etching using a resist film as a mask.
2. Description of the Background Art
The manufacturing process of a semiconductor device includes the step in which a thin film of metal such as aluminum or copper (a metal film) formed on a substrate such as a semiconductor wafer is etched by using a patterned resist film as a mask, thereby to obtain wiring of the semiconductor device.
This etching step is executed for example by dry etching such as RIE (reactive ion etching).
Since the power of reactive ions used in the above dry etching is extremely strong, the resist film is changed at a constant rate when the metal film etching is terminated. As a result, part of the resist film is changed to a reaction product such as polymer and deposited on the sidewall of the metal film. This reaction product cannot be removed in a subsequent resist removal step. It is therefore necessary to remove this reaction product before or after executing the resist removal step.
Conventionally, to remove a reaction product deposited on the sidewall of a metal film, a removal liquid that functions to remove the reaction product is supplied to a substrate after dry etching step or after resist removal step. Thereafter, the substrate is washed with deionized water, and the deionized water is dried by spinning.
In the meantime, due to the recent pattern miniaturization, the deionized water attached to a substrate might not be removed satisfactorily only by drying it spinning. If the deionized water remains on the substrate, there is a fear that the remaining deionized water is reacted with a thin film, air compositions, and contaminants in the air, thereby forming new contaminant.
Hence, if there is a process of supplying deionized water to a substrate, it is necessary to completely dry the substrate.
Particularly when deionized water remains on the substrate after the reaction product removal processing, a metal thin film part is often present on the substrate surface. This causes the problem that unnecessary oxide is formed by the reaction of the metal with the deionized water. Further, when this substrate is transported to a processing under vacuum, e.g., CVD, the deionized water attached to the substrate can adversely affect the processing.